Open Water, the second feature from director Chris Kentis, has been compared to both Jaws and The Blair Witch Project. That latter comparison is an apt one; the former is not. Aside from one coincident element - both movies feature sharks - there are few similarities between this indie horror movie and Steven Spielberg's 1975 blockbuster. On the other hand, despite the absence of a first-person approach and grainy black-and-white footage, there's more than a passing similarity to Blair Witch. Those who found that unexpected hit to be an instance of the Emperor's New Clothes will likely have a similar reaction to Open Water. But those who were creeped out by the tale of a trio of lost souls in the woods will find themselves equally terrified by what Kentis offers here.

The film starts out innocently enough, with a couple, Susan (Blanchard Ryan) and Daniel (Daniel Travis), headed to a tropical island for a vacation. Once there, they embark upon a scuba diving excursion, and that's where the problems begin. Due to an administrative snafu, they are accidentally left behind while under water. When they surface, they find themselves all alone in the middle of the deep blue sea. Actually, they're not alone. Their company ranges from the benign (tiny fish) to the dangerous (jelly fish) to the deadly (sharks). And, as they await rescue, they must deal with a variety of problems: nausea, dehydration, hunger, hypothermia, and exhaustion.

Approximately 60 minutes of the movie's 80 minute running time is spent with Susan and Daniel floating around in the ocean. At its best, Open Water is suspenseful and frightening - there are several excellent "boo!" moments, and Kentis never cuts away to relieve the tension. At its worst, the film is dull. There are long stretches when little happens. The characters bicker about who's at fault and discuss the various dangers they are facing. The dialogue is neither memorable nor inspired. It's pretty pedantic, and that causes some of Open Water's lulls to drag. Fortunately, even during those moments, the sense of danger lingers.

The film's best scene, from both an artistic and a suspense standpoint, occurs after dark, during a thunderstorm. Kentis elects not to use artificial lighting, so the only time we see the characters is when a flash of lightning illuminates them and the sharks that are circling them. Increasingly louder crashes of thunder momentarily obscure all sound, including the possible screams of one of the characters as the sharks move in. It's a chilling, unsettling five minutes, and, even if nothing else in Open Water had worked, this sequence alone would make the film worth consideration of a recommendation.

Blair Witch fans can count the similarities: characters are lost somewhere out of sight of civilization, bickering with each other about who's at fault, yet reliant upon one another for continued survival. A barely seen danger lurks just out of sight, becoming more bold with the approach of night fall. Plus, it's a low budget endeavor with little-known actors who use their own names (Blanchard Ryan's actual first name is Susan, but SAG rules do not allow her to be credited as "Susan Ryan," so she uses her middle name.) For those who hate open endings, at least Open Water concludes less cryptically than The Blair Witch Project.

The acting is a mixed bag. Blanchard Ryan, who has a number of small roles on her resume, is credible. This isn't an Oscar-wining performance, but she is able to deliver the dialogue convincingly and make us believe that she's desperate and frightened when the circumstances call for it. (Plus, her gratuitous nude scene isn't unwelcome.) Unfortunately, the same can't be said of Daniel Travis, whose wooden performance and lackluster delivery of his lines result in one of Open Water's most apparent black eyes. With a better actor in this role, Open Water might have been on the same level as Blair Witch. Although Travis doesn't sink the production, he causes it to take on water.

Despite its flaws, I welcome Open Water with great enthusiasm, because it offers genuine scares and chills without the self-aware, packaged feel of many horror/thriller films. There are moments (the thunderstorm in particular) when Open Water literally had me on the edge of my seat (that's a real state of body, not just a cliché). There aren't many movies capable of that, especially when you consider how jaded I have become. The movie relies upon the audience's imagination for much of its horror - little blood or violence is shown on-screen. For those to whom this sounds intriguing, Open Water is worth a trip to a theater. Just don't plan any scuba-diving expeditions soon after.